# ---
# title: 885. Spiral Matrix III
# id: problem885
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Math
# link: <https://leetcode.com/problems/spiral-matrix-iii/description/>
# hidden: true
# ---
# 
# On a 2 dimensional grid with `R` rows and `C` columns, we start at `(r0, c0)`
# facing east.
# 
# Here, the north-west corner of the grid is at the first row and column, and
# the south-east corner of the grid is at the last row and column.
# 
# Now, we walk in a clockwise spiral shape to visit every position in this grid.
# 
# Whenever we would move outside the boundary of the grid, we continue our walk
# outside the grid (but may return to the grid boundary later.)
# 
# Eventually, we reach all `R * C` spaces of the grid.
# 
# Return a list of coordinates representing the positions of the grid in the
# order they were visited.
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: R = 1, C = 4, r0 = 0, c0 = 0
#     Output: [[0,0],[0,1],[0,2],[0,3]]
#     
#     ![](https://s3-lc-upload.s3.amazonaws.com/uploads/2018/08/24/example_1.png)
#     
# 
# 
# 
# **Example 2:**
# 
#     
#     
#     Input: R = 5, C = 6, r0 = 1, c0 = 4
#     Output: [[1,4],[1,5],[2,5],[2,4],[2,3],[1,3],[0,3],[0,4],[0,5],[3,5],[3,4],[3,3],[3,2],[2,2],[1,2],[0,2],[4,5],[4,4],[4,3],[4,2],[4,1],[3,1],[2,1],[1,1],[0,1],[4,0],[3,0],[2,0],[1,0],[0,0]]
#     
#     ![](https://s3-lc-upload.s3.amazonaws.com/uploads/2018/08/24/example_2.png)
#     
# 
# 
# 
# **Note:**
# 
#   1. `1 <= R <= 100`
#   2. `1 <= C <= 100`
#   3. `0 <= r0 < R`
#   4. `0 <= c0 < C`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
